It is expected that failure prediction and optimum operation methods are determined by disposing a plurality of sensors in factory equipment and the like to analyze data obtained from the sensors. To transmit, record, or process analog data obtained from the sensors, the analog data is converted to digital data by using an analog-to-digital converter (ADC) for performing analog-to-digital conversion (AD conversion).
Since a plurality of types of sensors are used in such a field, the ADC in the circuit of each of the sensors is required to appropriately change the resolution (the number of bits) and the sampling rate according to the sensor.
Non-patent Literature 1 proposes an ADC that can vary the resolution for responding to a plurality of different types of sensor signals by using a small-scale circuit. In addition, Patent Literature 1 proposes means for adjusting the delay amount in an asynchronous successive approximation AD converter.